Motorcycle News, Editorials, Product Reviews and Bike Reviews

Kawasaki and Ryan Villopoto wrapped up the 2011 Monster Energy Supercross championship, both an AMA and an FIM World championship, just a couple of weeks ago in Las Vegas with the 2011 KX450F. Kawasaki has just announced the redesigned 2012 KX450F and its little brother, the KX250F. The KX250F has its share of championships, as well, including the Western Region Supercross Lites title Broc Tickle earned the same evening in Las Vegas. We have tested the KX250F several times (most recently, the 2011 model here).

Not resting on its laurels, Kawasaki has substantially redesigned both motocross bikes for 2012, and included groundbreaking technology in each model. The 2012 KX250F features not one, but two fuel injectors that work in tandem, including one placed inside the airbox. Meanwhile, the 2012 KX450F gains a rider-selectable launch control aimed at improving traction, and reducing wheel spin, in first and second gears. The system automatically disengages the first time the rider selects third gear.

Both bikes have numerous, additional changes to both chassis and engine, as well as transmission, for 2012, all of which are detailed in the following press releases from Kawasaki.

No other bike in its class has spent more time on the AMA Supercross podium than the Kawasaki KX™250F. The race-proven technology of the quarter-liter motocross leader returns for 2012, but with added enhancements that give the KX250F even more usable power, increased durability, and the best-handling chassis yet.

As the KX250F continues to lead the way in stadiums, it also continues to win the favor of enthusiast publications, who repeatedly name it a gold standard in motocross machinery. The KX250F offers cutting-edge technology right off the showroom floor, to give riders the winning edge on the track. Along with the KX250F’s race-proven performance, no other production motocrosser offers as much adjustability, fine-tuning capabilities and rider customization when it comes to motor and suspension. Right off the production line, the KX250F gives a factory advantage to the privateer racer – the difference between scratching for a podium and dominating a championship.

Second injector located in air boot.

For 2012, Kawasaki engineers sought to create a KX250F with even more impressive top-end performance, which they accomplished by equipping its Digital Fuel Injection (DFI®) system with a second fuel injector –a first for use on production motocross bikes– located near the airbox intake. The all-new “upstream” injector helps build a wider and more potent spread of power as rpm climbs. The two fine-mist atomizing injectors that feed the 250cc four-stroke powerplant are distinct in appearance with different body sizes, but deliver the same per-cycle capacity. Together, Kawasaki’s dual injectors pack a one-two punch, delivering a second dose of fuel on acceleration to increase the high-rpm power and overrev capabilities of the KX250F.

The addition of the second injector led to multiple modifications to the DFI system. An updated Electronic Control Unit (ECU) harnesses increased ignition power to run the DFI system. An accessory 2012 calibration kit is available and uses the same connector design as 2011, but features upgraded software and is compatible with Windows 7.

The 43mm Keihin throttle body is fitted with a new seal between the air inlet port and throttle position sensor unit designed to prevent fuel penetration from the upstream injector. The 2012 KX250F is also fitted with an air boot specifically altered to allow room for the upstream injector.

The dual-injector system is the central highlight of revisions made to the 2012 KX250F, but engineers didn’t stop there in their efforts to hone this 250cc masterpiece. A host of subtle changes throughout the motor continue to make it stronger and more durable throughout, all without weighing heavily on the price tag!

An upgraded crankshaft with redistributed inertial balance harmonizes with the more potent power delivery and also helps improve reliability. The bridged box-bottom piston and cylinder walls both feature new surface treatments to minimize wear and enhance long-term durability.

Modifications to the crankshaft, connecting rod, ACG stator and rotor change their rotational inertia, enhance durability and help provide a masterful balance to the high-performance engine. Overall, the crankshaft assembly features a balance factor of nearly 60 percent, which is right on par with factory Kawasaki race machines.

The seamless power delivery of the upgraded engine and DFI system is supplemented by a handful of transmission upgrades. A slightly shorter stroke of the shift fork and solid (rather than hollow) more smooth shift rods give the rider a more positive feel when changing gears, while keeping shift action as silky smooth as ever. The smooth-shifting transmission and reliably consistent clutch help keep the engine in the thick of its powerband throughout even the most challenging laps.

Sharp new styling touches enhance the appearance of the upgraded powertrain. The oil filler cap and engine plugs are colored blue, matching blue accents on the suspension adjusters and stylish new graphics.

Following the success of the 2011 KX250F and its impressive Separate Function Fork (SFF), the front suspension on the 2012 machine could have remained entirely untouched and still been a class leader. However, never content to leave exceptional alone, Kawasaki engineers analyzed feedback from the race teams and massaged the second-generation SFF accordingly.

Separate function fork

Fork spring rate is higher for 2012, going from a 9.1N/mm to a 9.5N/mm. A new, longer rebound spring improves corner approach and offers a more supple initial feel. In the left fork tube’s damper stack, the valving has been adjusted to complement the heavier spring rate. Two key features that retained from last year are the external fork preload adjuster and the trick titanium coating on the outer surface of the inner fork tubes.

The Showa-built shock also receives a stiffer spring rate, advancing from 51N/mm to 53N/mm. Along with a re-valve on the shock body, the compression damping restrictor and piston rod specs have been enhanced to refine the action of the shock. Complementing the shock upgrades is a thinner tie-rod on the suspension linkage with less rigidity, for smooth suspension action and improved traction. These refinements improve rear wheel traction and allow the KX250F to put the power down more effectively, making it easier than ever to grab the holeshot.

The KX250F is frequently praised for its rider interface and natural layout that fits a variety of sizes and abilities. Sleek and attractive bodywork includes a one-piece shroud and number-plate design. For 2012 the KX250F receives a new polyurethane seat that is more resistant to wear. The remainder of the chassis retains its finely crafted balance allowing the rider to have optimum leverage at all contact points for maximum performance gains on the track.

The KX250F is finished with quality race-proven components such as a Renthal aluminum handlebar and black alumite-coated aluminum wheels that are both lightweight and incredibly strong. A sleek, ribless rear hub and butted spokes further reduce unsprung weight, and factory-style graphics with a splash of blue that matches the alumite suspension adjusters and engine plugs finish off the sophisticated look of the class-winning machine, which is bound to top plenty of race podiums and enthusiast publication shootouts in the coming year.

Racers who ride their KX250F at designated events are eligible to receive support from Team Green™, Kawasaki’s amateur racing support program. Each year, Team Green provides regional support vehicles and highly trained technicians at more than 100 events throughout the United States, offering technical information and assistance to those who race Kawasaki products. Kawasaki also offers a comprehensive contingency program for amateur and professional riders who place well at designated events.

Authentic Kawasaki Accessories are available through Kawasaki dealers.

2012 KAWASAKI KX™450F – Prepare for Launch…

The race-winning power and confident handling of Kawasaki’s KX™450F motocrosser are back in an even sleeker and more advanced package than ever before. With racing always at the forefront, the KX450F’s latest technical innovations were developed from the factory know-how of the Monster Energy Kawasaki race team, with the final product representing an unmatched combination of cutting-edge innovation and race-proven components. Its best-in-class performance is facilitated by the highest level of rider adjustability and the most progressive electronics package ever seen on a production motocrosser. From the moment the gate drops, the 2012 KX450F is set to leave challengers in its dust.

The 2012 highlights begin with the Supercross-winning DNA of last year’s bike. The advanced design of the aluminum perimeter frame and dominating motor receive a host of refinements to create a more compact and mass-centralized chassis propelled by more usable power than ever. Headlining the technological charge, the KX450F features an all new Launch Control Mode, which is tuned to maximize traction out of the starting gate. This is accomplished without sacrificing any of the mid-range grunt or straight-line speed that made the KX450F famous.

2012 KX450F riders can easily activate the new Launch Control mode – a key feature never before seen on a production motocross bike. The push-button system is activated by a touch of the switch on the left handlebar, and optimizes off-the-line acceleration by altering ignition timing in first and second gears to help maximize grip and reduce the chance of excessive wheelspin. Shifting into third gear automatically deactivates Launch Control Mode and returns the ignition timing to the parameters of the installed ignition map. The Launch Control’s effectiveness is further enhanced by a chassis designed to maximize suspension performance and rear wheel traction.

No other production motocrosser offers a higher degree of adjustability to the rider interface or engine character than the new 2012 KX450F. With a choice of four different handlebar positions, two footpeg positions, and virtually unlimited ignition mapping capabilities – thanks to its advanced Digital Fuel Injection (DFI®) system – the KX450F is uniquely able to adapt to changing track and surface conditions and meet the needs of a surprisingly wide range of riders.

The DFI system comes with pre-programmed ignition maps, but new for 2012, these maps are interchangeable without the use of a laptop computer – or other separate electronic devices. Maps can quickly and easily be changed between three settings – standard, hard (conditions) and soft (conditions) – by swapping the DFI wire coupler cap clipped to the side of the steering head. No additional accessories are needed to alternate between preprogrammed settings – simply install the coupler cap with your desired ignition mode and start winning. The ECU is also still fully re-programmable by using the accessory KX FI Calibration Kit, the same tool used by Kawasaki factory and privateer teams in AMA and FIM racing.

The KX450F delivers improved mid- to high-end power and a wider powerband, thanks to numerous upgrades. The KX450F’s race-proven bridge-box bottom piston allows for optimum strength just like last year, but has been revised to optimize its rigidity balance and enhance mid- high-rpm character. A new thinner top piston ring with upgraded surface treatment reduces friction and helps improve throttle response. A new intake cam offers a slight increase in intake valve lift and allows the motor to breathe deeper, boosting power as well. The resulting combination offers a wider spread of torque and increased high-rpm performance. That extra power makes it to the ground more effectively than ever, thanks to the new electronics, plus multiple transmission upgrades and chassis improvements designed to complement the bolder power delivery.

The five-speed manual transmission handles the torque load with an ideal balance of precision and durability, thanks to an extra dog on the gears (up from 3 to 4) which improves shift feel. A new, shorter shift fork gives a smoother, more positive feel and reduces stress when changing gears, making shift action more efficient, while a new first gear is 2.8 mm thicker to enhance strength and durability. A new shift lever moves the pedal 3mm farther from the footpeg and offers greater durability. Finally, heavier clutch springs help channel the engine’s considerable torque when rocketing out of the gate.

Not only have the electronics, engine and gearbox been extensively upgraded, but a new frame and slimmer rider compartment also join the party for 2012. A total width reduction of 4mm across the main frame spars gives the 2012 KX450F the most slender mid-section ever. Chassis rigidity has been refined by altering the shape of the ribbing inside the new frame, creating more flex in the upper portion and stiffening the lower sections around the swingarm pivot. These changes helped increase rear wheel traction and also allowed additional room for the alternate footpeg mounting position.

In another industry-first innovation, the 2012 KX450F offers two footpeg positions to choose from. The alternate position places the footpegs five millimeters lower than stock, which not only allows for taller riders, but lowers the center of gravity and gives the rider a lower point of view, adding to both physical and psychological stability.

The tie rod arm of the Uni-Trak® rear suspension linkage is now slimmer, offering slightly less rigidity for added rear-wheel traction. Kawasaki will also offer an optional rear suspension tie rod, which can be used to reduce seat height. The optional unit is one millimeter shorter than stock, which translates to a six millimeter reduction in seat height – a subtle but effective change for “inseam challenged” riders.

The Kayaba rear shock features a beefy 50mm piston and also receives a top-shelf Kashima Coat surface treatment in its internals. Ample adjustability of the shock body helps ensure smooth, reliable and consistent action of the rear suspension that not only offers superior performance, but also helps the rider relax and conserve valuable strength on the way to the finish line.

Up front, the Kayaba Air-Oil-Separate (AOS) fork keeps oil and air in separate chambers for remarkably stable damping performance during long motos. A revised lower triple clamp contributes to improved fork action. The new clamp can be recognized by its rear-opening design. The super-hard Diamond-Like Carbon (DLC) coating on the outer surface of the inner fork tubes and high-tech Kashima Coat treatment on the inner surface of the outer fork tubes significantly reduce drag compared to a standard fork assembly and help deliver supple, fade-free fork action.

Mass centralization and a lower center of gravity were additional targets for the 2012 KX450F, so a new fuel tank, upgraded bodywork and a shorter muffler help relocate weight toward the center of the motorcycle and make the new KX more nimble than ever.

The new fuel tank has a shorter overall height and a narrower top section, which forms a straighter, smoother line with the seat and allows greater freedom of movement for the rider. The new fuel tank also houses an upgraded fuel pump, which is lighter in weight thanks to an integrated filter cover which wraps around the inlet port and acts as a fuel trap. This also eliminates the need for a pressure regulator fuel return hose.

The new header pipe has a shorter length and features a tapered mid-section. The new silencer is a full 60mm shorter than its predecessor, but features a revised cross-section and the same overall volume as the 2011 model and meets noise regulations.

A new rigid-mount wave-type front brake rotor, slimmer front tire and new seat foam add to the lengthy list of improvements made to the 2012 KX450F. Minimalist body work, revised shrouds and smaller number plates contribute to the slender feel and sleek new looks of Kawasaki’s flagship motocross machine. Sparing no attention to detail, the seams between the radiator shrouds, seat and side covers are very flush fitting, which helps prevent snags and allow the rider to alter position and maneuver the bike more effectively.

A blue alumite finish on the oil cap and two caps on the generator cover highlight the upgraded appearance of the KX450F motor, and match the blue finish on the suspension adjusters and splashes of color in the new graphics. A new embossed logo on the clutch cover features a trick design that reveals a raised Kawasaki racing insignia as the black paint is worn away by the rider’s boot.

The 2011 KX450F is available in Kawasaki Lime Green, with black alumite-coated rims, blue anodized highlights and aggressive graphics.

Racers who ride their KX450F at designated events are eligible to receive support from Team Green™, Kawasaki’s amateur racing support program. Each year, Team Green provides regional support vehicles and highly trained technicians at more than 100 events throughout the United States, offering technical information and assistance to those who race Kawasaki products. Kawasaki also offers a comprehensive contingency program for amateur and professional riders who place well at designated events.

2012 Kawasaki KX™450F

Features and Benefits

At a glance…

All-new Launch Control Mode increases the chance of nailing the holeshot

No battery needed; the engine can be started with only three rotations of the crankshaft using the electricity generated by a single kick of the starter

The system delivers electricity to FI system in sequence: first the ECU, then the fuel pump, and finally the injector for quick, easy starting

The compact, lightweight ECU, located on the front of the steering head behind the number plate, was designed specifically for motocross use. The fuel pump relay is integrated with the ECU to help cope with the shocks and vibrations of motocross riding

The tool can also be used as a data logger, recording up to six hours of data, including engine rpm, degree of throttle opening, engine boost, coolant temp, air temp, ignition timing, fuel adjustments, gear position and system voltage

2012 software program is updated for compatibility with 64-bit operating systems such as Windows 7

Easy Starting

Revised shape of kickstart ratchet enables lever to return to start position more smoothly

Strong output from the large ACG rotor provides enough electrical power for the battery-less FI system to enable true one-kick starting without using a battery

Equipped with an automatic compression release (ACR) system for quick and easy starting. The dual-weight centrifugal decompression system is fitted to the exhaust cam

Compression release features 1.0mm of valve lift, to minimize the required kicking power

Lightweight Aluminum Fuel Pump

Fuel pump now features a one-piece filter cover and body, eliminating the need for fuel return tube from pressure regulator and contributing to weight reduction

Features a plastic (formerly rubber) fuel filter cover that wraps around the inlet port and acts as a fuel trap to help ensure a stable fuel supply during vigorous motocross riding

New clutch case cover features embossed logo, designed to be revealed as rider’s boot wears away black paint

Close-Ratio 5-Speed Transmission

5-Speed transmission and low-rpm engine response combination offers riders more gear options for traversing rough sections or getting into the rhythm of a course easily so they can focus more on racing

Diamond-Like Carbon (DLC) coating on the outer surface of the inner fork tubes offers minimum stiction when the fork is exposed to lateral forces that would usually hamper slide action. The result is improved fork response, especially during cornering

Friction-reducing Kashima Coat on the inside of the fork’s outer tubes contributes to smooth suspension action (especially at the initial part of the stroke) and a superb ride feel

16 Comments

This is ridiculous! A few years back the AMA wouldn’t let Aprilia race it’s two cylinder because they (the AMA) didn’t want costs to increase. Four strokes cost 10 times as much as two strokes so why did the AMA even go with them? I love to ride(two strokes) but four stroke MXers are killing amateur racing. Ask any track owner about the gate count. I can only imagine it getting worse with all the electronic gizmos.

Your comparing apples and oranges or 2-stroke with 4 stroke which is really of little value. Not to mention the fact that the press release states that fuel mapping is, “easily selectable via DFI wire coupler caps, no computer necessary”. The PC interface is optional and mostly for data capture so no archaic software emulators necessary 30 years hence. Besides I’m sure that Sudco Int’l the same place where you can still get carb parts for your CR will have injectors and much more efficient Linux based software packages available for these vintage bikes.

What has trailering a bike got to do with how much you’re willing to pay for it? Would you ride either one of these bikes to your local off rode riding spot if they were street legal. Where I live it’s about 100 miles of mostly freeway to get to the nearest OHV area so why in world would I do anything but haul it out there.

I can relate to Chris’s comment.
I can only have one bike…so, if i were to buy this i would like to use it as much as possible (streets) when im away from the trails in order to justify its MSRP enough, but thats just me.
To each its own, im sure some of us here wouldn’t mind riding to the trails just cause we don’t have the pockets to own a decent trailer and hauling truck(me again).

” why in the world would I(harryfxr) do anything but to haul it out there ”

YUP, why not make a street legal version of it OR BOTH ? Soften the engine, make the top end go 26,600 miles betwen valve clearance checks (somehow) like the YAMAHA WR250X, 4+Gallon fuel tank, some cheap mirrors, a decent headlight, a battery/starter(but keep the kick starter), Black 17″ wheels and presto !

New Model with almost no R&D Costs ! And all the cost for all the fancy equipment(DLC Forks, Fancy new EFI, New Frame, etc) can be distributed AND dampened over a wider range on your lineup making it less costly per unit.

And then dump that lame excuse for a SUMO that the KLX250SF tries to be.

WR250R engine isn’t the same as the YZ250F engine (which is btw the most ancient MX engine today, including two-strokes and niche manufactures), not on mechanics and certainly not in performance.

As to why Kawasaki or any other Japanese manufacturer doesn’t offer a (barely) street-legal version of its 450 enduro, who know, maybe they don’t want to make money? KTM, Husqvarna and other make them, however, and with greater performance to boot!